The proposed studies will build upon our recent research into genetic networks. We will be extending these, with an initial emphasis on colon and breast cancer, to include serum, urine, and other physiological analyses to develop models of a 'cancer susceptibility state' in order build better mouse models to investigate cancer predisposition and the mechanism by which an individuals genetic makeup and environmental exposure influences susceptibility and eventual response to therapy. Our definition of the cancer susceptibility state will draw from high-throughput methods for defining RNA and protein expression and high-throughput methods for defining genes that control that expression. We will also be addressing several critical issues in cancer research including how diet influence genetic networks associated with cancer susceptibility, the role of obesity in contributing to cancer susceptibility, how environmental exposures differ from genetic induction, among others. This research is definitely a new paradigm for cancer research and should lead to new biomarkers for susceptibility, a better understanding of intermediate phenotypes contributing to cancer susceptibility, and the role of biological plasticity and network switching in cancer predisposition with direct applications to human biology.